Screen Space Reflection Flickering During Animation
This is why you should use EEVEE more as a low budget render, fast interaction before making the final render with Cycles.
EEVEE is real-time, therefore less quality. The flickering probably only gonna disappear if you turn off the screen space reflection and use raytraced reflections
You can also use later Blender releases that improve SSRF.
I've been using rasterized screen space effects elsewhere and that flickering appears constantly, so I confidently say it's inherent to kind of SS effects, so it's probably impossible to remove it completely, only to minimize by bumping EEVEE render settings.